1. Technical Field
This invention relates generally to wear bars or traction runners or bars used on the lower running surface of a ski for a snowmobile or the like to reduce wear on the skis and to improve steering traction, particularly on icy surfaces.
2. Related Art
It is common in the field of performance snowmobiling to outfit the skis of the snowmobile with wear bars or runners in order to improve the steering traction and thus handling of the snowmobile. The use of such traction runners is particularly common for races carried out on an ice track.
The typical traction bar used in performance racing of snowmobiles is constructed from a length of steel rod that serves as the body of the traction bar. A pair of threaded studs are welded to the top side of the bar and are received in associated mounting holes provided in the skis to enable the wear bar to be mounted removably on the skis by corresponding fastener nuts threaded onto the mounting studs on the top side of the skis. An opposite lower side of the wear bar is typically formed to include a channel in which a wear strip of carbide material is metallurgically bonded and finished to a knife edge to present a sharp, wear-resistant traction strip extending lengthwise of the ski and acting to bite into the terrain to provide enhanced traction and steerability, particularly on icy terrain.
One drawback to the use of wear bars is the weight which they add to the snow machine. However, the benefits resulting from the increased traction and handling far outweigh the negative effects of added weight, and thus the use of traction bars of the general type described above have become accepted as an essential accessory for use in performance snowmobile racing. Prior to this invention, efforts to use lighter weight materials for the traction bar, such as aluminum, have failed due to the inability to find a suitable way to form a metallurgical bond of the aluminum traction bar and ceramic wear strip insert that would hold up under the abusive conditions that such traction strips are subjected to, including repeated pounding and torquing from sudden impacts with the terrain and frequent changes in the steering direction. These forces introduce stress at the interface of the ceramic wear strip and the parent traction bar materials, causing a poorly bonded carbide wear strip of the prior aluminum traction bars to fail and separate from the aluminum body. It is an object of the present invention to overcome or greatly minimize the disadvantages and limitations of the prior traction bars.